U.S. patent application number 14/955360 was filed with the patent office on 2017-06-01 for selenization/sulfurization process apparatus for use with single-piece glass substrate.
The applicant listed for this patent is NATIONAL CHUNG SHAN INSTITUTE OF SCIENCE AND TECHNOLOGY. Invention is credited to TSAN-TUNG CHEN, JEN-CHIEH LI, MING-JUNE LIN, WEN-CHUEH PAN, YIH-HSING WANG, SHIH-SHAN WEI, TIEN-FU WU.
Application Number | 20170155005 14/955360 |
Document ID | / |
Family ID | 58777360 |
Filed Date | 2017-06-01 |
United States Patent
Application |
20170155005 |
Kind Code |
A1 |
PAN; WEN-CHUEH ; et
al. |
June 1, 2017 |
SELENIZATION/SULFURIZATION PROCESS APPARATUS FOR USE WITH
SINGLE-PIECE GLASS SUBSTRATE
Abstract
A selenization/sulfurization process apparatus for use with a
single-piece glass substrate is characterized by two chambers for
heating up a glass substrate quickly and performing
selenization/sulfurization on the glass substrate to not only
prevent the glass substrate from staying at a soaking temperature
of a softening point for a long period of time but also increase
the thin-film selenization/sulfurization temperature according to
the needs of the process to thereby reduce the duration of soaking
selenization/sulfurization, save energy, and save time. The glass
substrate undergoes reciprocating motion in the chambers to not
only attain uniform temperature throughout the glass substrate but
also distribute a selenization/sulfurization gas across the glass
substrate uniformly during the selenization/sulfurization
operation. The recycled liquid selenium/sulfur and inert gas are
reusable to thereby reduce material costs.
Inventors: |
PAN; WEN-CHUEH; (TAOYUAN
CITY, TW) ; WANG; YIH-HSING; (TAOYUAN CITY, TW)
; LIN; MING-JUNE; (TAOYUAN CITY, TW) ; LI;
JEN-CHIEH; (TAOYUAN CITY, TW) ; WEI; SHIH-SHAN;
(TAOYUAN CITY, TW) ; WU; TIEN-FU; (TAOYUAN CITY,
TW) ; CHEN; TSAN-TUNG; (TAOYUAN CITY, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NATIONAL CHUNG SHAN INSTITUTE OF SCIENCE AND TECHNOLOGY |
Taoyuan City |
|
TW |
|
|
Family ID: |
58777360 |
Appl. No.: |
14/955360 |
Filed: |
December 1, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 31/0322 20130101;
H01L 21/02568 20130101; Y02E 10/541 20130101; Y02P 70/521 20151101;
H01L 21/02614 20130101; C23C 14/5866 20130101; C23C 14/541
20130101; H01L 21/6776 20130101; Y02P 70/50 20151101; H01L 31/18
20130101 |
International
Class: |
H01L 31/032 20060101
H01L031/032; H01L 31/18 20060101 H01L031/18 |
Claims
1. A selenization/sulfurization process apparatus for use with a
glass substrate, comprising: a first chamber having a first gate
and a second gate, wherein the first gate and the second gate are
disposed on two unconnected sides of the first chamber,
respectively; a first hot roller heating module disposed in the
first chamber and between the first gate and the second gate; a
first heater disposed in the first chamber and positioned on a top
side and a bottom side of the first hot roller heating module; a
second chamber having a third gate and disposed beside the second
chamber; a second hot roller heating module disposed in the second
chamber and positioned proximate to the third gate; a second heater
disposed in the second chamber and positioned on a top side and a
bottom side of the second hot roller heating module; a heating
temperature equalizing plate disposed in the second chamber to
allow the radiation heat from heating lamps to be distributed
uniformly to the glass substrate; a gas uniform distribution module
connected to the second chamber to thereby introduce a gas into the
second chamber; a gas recycling module connected to the second
chamber to thereby recycle the gas in the second chamber; an
interface channel connected to the first gate of the first chamber
and the third gate of the second chamber, respectively; and a
non-contact temperature measuring device disposed in the interface
channel.
2. The selenization/sulfurization process apparatus of claim 1,
wherein the first hot roller heating module has a plurality of
first heating rollers each having therein a first roller heating
unit.
3. The selenization/sulfurization process apparatus of claim 2,
wherein the first heating rollers are made of one of graphite,
silicon oxide ceramic, zirconium oxide ceramic, quartz and
Inconel.
4. The selenization/sulfurization process apparatus of claim 3,
wherein outer surfaces of the first heating rollers are made of a
plasma-clad ceramic thin-film.
5. The selenization/sulfurization process apparatus of claim 1,
wherein the second hot roller heating module has a plurality of
second heating rollers each having therein a second roller heating
unit.
6. The selenization/sulfurization process apparatus of claim 5,
wherein the second heating rollers are made of one of graphite,
silicon oxide ceramic, zirconium oxide ceramic, quartz and
Inconel.
7. The selenization/sulfurization process apparatus of claim 6,
wherein outer surfaces of the second heating rollers are made of a
plasma-clad ceramic thin-film.
8. The selenization/sulfurization process apparatus of claim 1,
wherein the gas uniform distribution module comprises: a vapor
producing unit for producing one of selenium vapor and sulfur vapor
and controlling an output level of the one of selenium vapor and
sulfur vapor by pressure adjustment; an inert gas control unit for
controlling an output level of an inert gas; a gas mixing unit
connected to the vapor producing unit and the inert gas control
unit to thereby mix and output the vapor produced by the vapor
producing unit and the inert gas output by the inert gas control
unit; a mixed gas cracking heating unit connected to the gas mixing
unit; and a mixed gas distributing unit for connecting the gas
cracking heating unit and the second chamber and distributing
uniformly the gas output by the mixed gas cracking heating unit on
the glass substrate in the second chamber.
9. The selenization/sulfurization process apparatus of claim 1,
wherein the gas recycling module comprises: a gas drawing unit
connected to the second chamber via a gas drawing channel to
thereby draw out the gas from the second chamber; a condensation
unit connected to the gas drawing unit to thereby separate the
vapor and the inert gas drawn out by the gas drawing unit; and a
collecting unit connected to the condensation unit to collect the
vapor and the inert gas thus separated.
10. The selenization/sulfurization process apparatus of claim 1,
wherein the first heater comprises a plurality of heating
lamps.
11. The selenization/sulfurization process apparatus of claim 1,
wherein the second heater comprises a plurality of heating lamps
and a plurality of heating temperature equalizing boards.
12. The selenization/sulfurization process apparatus of claim 1,
further comprising a first thermal insulation pad disposed on an
inner wall of the first chamber.
13. The selenization/sulfurization process apparatus of claim 1,
further comprising a second thermal insulation pad disposed on an
inner wall of the second chamber.
14. The selenization/sulfurization process apparatus of claim 1,
wherein heating temperature equalizing plates made of graphite are
disposed in the second chamber to allow the radiation heat from
heating lamps to be distributed uniformly to the glass
substrate.
15. The selenization/sulfurization process apparatus of claim 1,
wherein mixed gases are distributed onto the surface of the glass
substrate uniformly, a mixed gas distributing unit is formed by
coupling together a plate and two halves of a round pipe, wherein a
plurality of through gas-emitting holes is disposed at the lower
end of the round pipe and the flat board, such that a mixture of
selenium/sulfur vapor and an inert gas passes the through
gas-emitting holes to distribute uniformly across the glass
substrate.
Description
FIELD OF TECHNOLOGY
[0001] The present invention relates to selenization/sulfurization
process apparatuses and more particularly to a
selenization/sulfurization process apparatus for use with a
single-piece glass substrate.
BACKGROUND
[0002] Conventional solar cells with copper-indium-gallium-selenium
(Cu/In/Ga/Se, CIGS) thin-film are made from direct bandgap
semiconductor materials, with bandgap of 1.04 eV through 1.68 eV,
and feature a very high optical absorption coefficient, a wide
optical absorption range and high stability of long-term
illumination, and a high possibility potential to achieve low
material and manufacturing costs and exhibit satisfactory
conversion efficiency. Hence, CIGS solar cells are presently the
most promising solar cells.
[0003] Major conventional technologies applicable to the
manufacturing of CIGS solar cells are mostly based on vacuum
processes, including Cu/In/Ga precursor sputtering deposition then
selenization and 3 stages co-evaporation process. In this regard,
sputtering selenization process is currently the main mass
production method in CIGS solar cell market. There are two types of
sputtering selenization processes. One of the two types of
sputtering selenization requires a high-temperature furnace and
involves introducing H.sub.2Se into closed vacuum to undergo
high-temperature selenization, wherein multiple pieces of
substrates are placed in a high-temperature furnace in each
instance on condition that a precursor layer is disposed on the
substrate surface. This type of sputtering selenization entails
creating vacuum, introducing a gas, heating, soaking, lowering the
temperature to room temperature, and discharging the gas, in a
cyclical course, thereby taking much time (up to 10 hours).
However, the multiple-piece process is unlikely to attain
consistent uniformity but consumes much power and much pricey
materials as well as incurs high costs. Another type of sputtering
selenization is based on rapid thermal processing (RTP) and further
divided into two categories. One category involves depositing a
selenium thin-film on a substrate to function as a portion of a
precusor layer and then performing rapid selenization by continuous
temperature raising/soaking/temperature lowering and internal
delivery. Alternatively, rapid selenization carried out by
temperature raising/soaking/temperature lowering takes place in
consecutive chambers which can be opened/insulated. The other
category involves performing rapid selenization at selenium vapor
state (cracking selenium) in the presence of a combination of a
selenium thin-film and a precusor layer or in the presence of a
precusor layer free of any selenium thin-film.
[0004] Manufacturing copper-indium-gallium-selenium-sulfur (CIGSS)
thin-film solar cells on a soda-lime glass substrate requires
producing a CIG (copper-indium-gallium) precursor by vacuum
sputtering and producing a CIGSS absorption layer by a combination
of a rapid thermal processing (RTP) process and the
selenization/sulfurization technique to thereby advantageously
render the manufacturing process high-quality, speedy and conducive
to large-area production. Regarding to the design of a RTP
selenization process, the stress (tensile or compressive stress)
between the layers and the designed structures (single layer or
multi-layer) depend on crystal orientation (amorphous or
polycrystalline) of the Cu--In--Ga precusor film. In this regard,
the design of a system in its entirety calls for the following
considerations: (1) selenization/sulfurization temperature; (2)
raising rate of the temperature and lowering rate of the
temperature; (3) selenization/sulfurization duration and
temperature distribution in each stage; (4) selenium/sulfur
cracking module design; (5) high-temperature uniformity over entire
glass substrate design; (6) chamber airtight and glass substrate
moves smoothly oscillation in chamber and transfer quickly between
two chambers; (7) ways of distributing selenium/sulfur atmosphere
uniformly; and (8) selenium/sulfur pollution prevention and
recycling mechanism. The aforesaid considerations are crucial
factors in designing a system in its entirety, wherein rapid
selenization occurs in selenium vapor state or rapid selenization
occurs in selenium vapor state with a selenium evaporation film
precursor.
[0005] Techniques and methods for manufacturing CIGS solar cells
abound. However, the prior art has not yet successfully disclosed
any process that meets both the demand for cost-effectiveness and
the demand for high efficiency. In this regard, the major
bottleneck lingers because stable technology about a large-area
CIGS solar cell process remains undeveloped. Main issues pertaining
to the process apparatus include: uneven irradiation heat during
the process carried out with a large-area glass substrate; uniform
distribution of selenium vapor; selenium vapor recycling; and
deformation of a glass substrate during a high-temperature process.
U.S. Pat. No. 5,578,503 discloses that a process is performed at a
heating speed to increase the temperature by at least 10.degree. C.
per second to thereby prevent uneven distribution of thin-film
surface tension which might otherwise be caused by liquefied
element selenium in the course of selenization and the resultant
solar cell conversion efficiency deterioration arising from poor
crystallization. However, the glass substrate is likely to break
apart during the process when a large-area glass substrate is
heated up at a heating speed to increase the temperature by at
least 10.degree. C. per second. US 2010/0226629A1 discloses a way
of preventing selenium contamination during a continuous
selenization mass production process, but US 2010/0226629A1 fails
to address an issue, that is, the uniform heating and recycling of
selenium.
[0006] Accordingly, it is imperative to provide a
selenization/sulfurization process apparatus for use with a glass
substrate, so as to overcome the aforesaid drawbacks of the prior
art.
SUMMARY
[0007] It is an objective of the present invention to provide a
selenization/sulfurization process apparatus capable of heating a
single-piece glass substrate uniformly and performing
selenization/sulfurization thereon uniformly.
[0008] Another objective of the present invention is to provide a
selenization/sulfurization process apparatus for replacing
selenization or sulfurization of toxic H.sub.2Se or H.sub.2S in a
vacuum environment with cracking selenium or mixing sulfur with an
inert gas in a near-atmospheric pressure environment.
[0009] Yet another objective of the present invention is to provide
a selenization/sulfurization process apparatus capable of recycling
and thus reusing excess selenium vapor or sulfur vapor in a process
to thereby reduce material costs.
[0010] In order to achieve the above and other objectives, the
present invention provides a selenization/sulfurization process
apparatus for use with a glass substrate, comprising a first
chamber, a first hot roller heating module, a first heater, a
second chamber, a second hot roller heating module, a second
heater, a gas uniform distribution module, a gas recycling module,
an interface channel and a temperature measuring device. The first
chamber has a first gate and a second gate. The first gate and the
second gate are positioned on the front side and back side of the
first chamber, respectively. The first hot roller heating module is
disposed in the first chamber and between the first gate and the
second gate. The first heater is disposed in the first chamber and
positioned on the top side and bottom side of the first hot roller
heating module. The second chamber has a third gate disposed at the
front side of the second chamber. The second hot roller heating
module is disposed in the second chamber and positioned proximate
to the third gate. The second heater is disposed in the second
chamber and positioned on the top side and bottom side of the
second hot roller heating module. The gas uniform distribution
module is connected to the second chamber to thereby introduce a
mixing gas into the second chamber. The gas recycling module is
connected to the second chamber to recycle the gas in the second
chamber. The interface channel is connected to the second gate of
the first chamber and the third gate of the second chamber. The
temperature measuring device is disposed in the interface
channel.
[0011] In an embodiment of the present invention, the first hot
roller heating module has a plurality of first heating rollers each
of which has therein a first roller heating unit.
[0012] In an embodiment of the present invention, the first heating
rollers are made of graphite, silicon oxide ceramic, zirconium
oxide ceramic, quartz or Inconel alloy.
[0013] In an embodiment of the present invention, the second hot
roller heating module has a plurality of second heating rollers,
and each second heating roller has therein a second roller heating
unit.
[0014] In an embodiment of the present invention, the second
heating rollers are made of graphite, silicon oxide ceramic,
zirconium oxide ceramic, quartz or Inconel alloy.
[0015] In an embodiment of the present invention, the gas uniform
distribution module comprises a vapor producing unit, an inert gas
control unit, a gas mixing unit with a selenium vapor discharge
control unit, a mixed gas cracking heating unit and a mixed gas
distributing unit. The vapor producing unit produces selenium vapor
or sulfur vapor and controls the output level of the selenium vapor
or sulfur vapor by pressure adjustment. The inert gas control unit
controls the output level of the inert gas. The mixing gas is mixed
in the selenium vapor producing unit. The mixed gas cracking
heating unit is connected to the gas mixing unit. The mixed gas
distributing unit is connected to the gas cracking heating unit to
distribute the gas uniformly through the channel to the nozzles
onto the glass substrate in the second chamber.
[0016] In an embodiment of the present invention, the gas recycling
module comprises a gas drawing unit, a condensation unit and a
collecting unit. The gas drawing unit is connected to the second
chamber via a gas drawing channel to draw out the gas from the
second chamber. The condensation unit is connected to the gas
drawing unit to separate the vapor and inert gas drawn out by the
gas drawing unit. The collecting unit is connected to the
condensation unit to collect the vapor and inert gas thus
separated.
[0017] In an embodiment of the present invention, the first heater
comprises a plurality of heating lamps.
[0018] In an embodiment of the present invention, the second heater
comprises a plurality of heating lamps and a plurality of heating
temperature equalizing plates.
[0019] In an embodiment of the present invention, the selenization
or sulfurization process apparatus further comprises a first
thermal insulation pad disposed on the inner wall of the first
chamber.
[0020] In an embodiment of the present invention, the selenization
or sulfurization process apparatus further comprises a second
thermal insulation pad disposed on the inner wall of the second
chamber.
[0021] In an embodiment of the present invention, the temperature
measuring device is of non-contact style.
[0022] In an embodiment of the present invention, the selenization
or sulfurization process apparatus further comprises a fourth gate
disposed at the back end of the second chamber.
[0023] Hence, the selenization or sulfurization process apparatus
of the present invention is characterized by two chambers for
heating up a glass substrate quickly and performing selenization or
sulfurization on the glass substrate to not only prevent the glass
substrate from staying at a soaking temperature of a softening
point for a long period of time but also increase the thin-film
selenization/sulfurization temperature according to the needs of
the process to thereby reduce the duration of soaking selenization
or sulfurization process, save energy, and save time. The glass
substrate undergoes reciprocating motion in the chambers to not
only attain uniform temperature throughout the glass substrate but
also distribute a selenization/sulfurization gas across the glass
substrate uniformly during the selenization/sulfurization process.
The recycled liquid selenium/sulfur and inert gas are reusable to
thereby cut material costs.
BRIEF DESCRIPTION
[0024] Objectives, features, and advantages of the present
invention are hereunder illustrated with specific embodiments in
conjunction with the accompanying drawings, in which:
[0025] FIG. 1 is a schematic view of a rapid thermal processing
device in an embodiment of the present invention;
[0026] FIG. 2 is a schematic view of a selenization or
sulfurization soaking device in an embodiment of the present
invention;
[0027] FIG. 3 is a function block diagram of a gas uniform
distribution module in an embodiment of the present invention;
[0028] FIG. 4 is a schematic view of a mixed gas distributing unit
in an embodiment of the present invention;
[0029] FIG. 5 is a function block diagram of a gas recycling module
in an embodiment of the present invention; and
[0030] FIG. 6 is a schematic view of the rapid thermal processing
device and the selenization/sulfurization soaking device coupled
together in an embodiment of the present invention.
DETAILED DESCRIPTION
[0031] Referring to FIG. 1, there is shown a schematic view of a
rapid thermal processing (RTP) device 10 in an embodiment of the
present invention. The rapid thermal processing device 10 raises
the temperature of a glass substrate 1 uniformly and quickly with a
view to providing a device capable of heating up a glass substrate
at a speed, say 10.degree. C./s, switching the glass substrate
quickly, and allowing the glass substrate to undergo reciprocating
motion. The rapid thermal processing device 10 has a first chamber
100, a first hot roller heating module 110 and two first heaters
120, 121.
[0032] The first chamber 100 has a first gate 101 and a second gate
102 which open or shut movably. The first gate 101 and the second
gate 102 are disposed on the front side and back side of the first
chamber 100, respectively. The first hot roller heating module 110
is disposed in the first chamber 100 and positioned between the
first gate 101 and the second gate 102. The first heaters 120, 121
are disposed in the first chamber 100. The first heater 120 is
disposed on the top side of the first hot roller heating module
110. The first heater 121 is disposed on the bottom side of the
first hot roller heating module 110.
[0033] During the process, the rapid thermal processing device 10
enters a vacuum state with a vacuum pump (not shown) to insulate
itself from the outside and thus form an airtight space by the
first chamber 100, the first gate 101 and the second gate 102. The
vacuum state is a low degree of vacuum state. The glass substrate 1
moves into and out of the first chamber 100 through the first gate
101 and the second gate 102.
[0034] During the process, the glass substrate 1 is placed on the
first hot roller heating module 110, such that the first hot roller
heating module 110 drives the glass substrate 1 to undergo
reciprocating motion repeatedly. The first hot roller heating
module 110 has a plurality of first heating rollers 111, and a
first roller heating unit 112 is disposed in each first heating
roller 111. The first roller heating units 112 heat up the first
heating rollers 111 uniformly, such that the temperature of the
contact surfaces of the first heating rollers 111 in contact with
the glass substrate 1 and the temperature of the glass substrate 1
are kept within a specific range of temperature. Furthermore, the
first heating rollers 111 are made from materials which are
tolerant to high-temperature selenization/sulfurization process,
such as graphite, silicon oxide ceramic, zirconium oxide ceramic,
quartz or Inconel alloy, and outer surfaces of the first heating
rollers 111 are made of a plasma-clad ceramic thin-film to increase
their surface friction coefficient and maintain a certain thermal
conductivity coefficient.
[0035] The first heaters 120, 121 heat up the glass substrate 1 and
the CIGS thin-film (not shown) on the upper surface of the glass
substrate 1. In this embodiment, the first heaters 120, 121 are
heating lamps, as heating lamps have a high heating speed.
Selectively, specific heating lamps are employed to emit light rays
with a wavelength which matches the wavelength of the heat energy
absorbed by the CIGS thin-film on the upper surface of the glass
substrate 1 and the glass substrate 1, thereby increasing the
heating efficiency.
[0036] To contain the heat in the first chamber 100 and thus
maintain the temperature in the first chamber 100, a thermal
insulation pad 130 (such as a graphite blanket) is disposed on the
inner wall of the first chamber 100.
[0037] Referring to FIG. 2, there is shown a schematic view of a
selenization or sulfurization soaking device 20 in an embodiment of
the present invention. The selenization/sulfurization soaking
device 20 performs a selenization or sulfurization process on the
glass substrate 1 uniformly so as to perform high-temperature
soaking selenization or sulfurization process on the glass
substrate, moving the glass substrate, and switch the rolling
direction of the hot roller to effectuate the reciprocating motion
of the glass substrate. The selenization or sulfurization soaking
device 20 comprises a second chamber 200, a second hot roller
heating module 210, a second heating module 220, a gas uniform
distribution module 230 and a gas recycling module 240.
[0038] The second chamber 200 has a third gate 201 which opens or
shuts movably and a fourth gate 202 provided as needed. The second
hot roller heating module 210 is disposed in the second chamber 200
and positioned between the third gate 201 and the fourth gate 202.
The second heater 220 is disposed in the second chamber 200 and
positioned on the top side and bottom side of the second hot roller
heating module 210.
[0039] During a process operation, like the rapid thermal
processing device 10, the selenization/sulfurization soaking device
20 is insulated from the outside by the second chamber 200, the
third gate 201 and the fourth gate 202 to form an airtight space
with a low degree of vacuum state. The glass substrate 1 moves into
or out of the second chamber 200 via the third gate 201 and the
fourth gate 202.
[0040] During a process operation, the glass substrate 1 is placed
on the second hot roller heating module 210. The second hot roller
heating module 210 drives the glass substrate 1 to undergo
reciprocating motion repeatedly. Like the first hot roller heating
module 110, the second hot roller heating module 210 has a
plurality of second heating rollers 211. Each second heating roller
211 has therein a second roller heating unit 212. Furthermore, the
second heating rollers 211 are made from materials which are
tolerant to high-temperature selenization/sulfurization process,
such as graphite, silicon oxide ceramic, zirconium oxide ceramic,
quartz or Inconel alloy, and outer surfaces of the second heating
rollers 211 are made of a plasma-clad ceramic thin-film to increase
their surface friction coefficient and maintain a certain thermal
conductivity coefficient.
[0041] The second heating module 220 heats up the glass substrate 1
and the CIGS thin-film (not shown) on the upper surface of the
glass substrate 1. In this embodiment, the second heater 220
comprises a plurality of heating lamps 221 and a plurality of
heating temperature equalizing plates 222. The heating lamps 221
heat up the heating temperature equalizing boards 222 to the
temperature required for the process. Furthermore, a radiation
reflector (not shown) is disposed beside the second chamber 200
which houses the glass substrate 1 to compensate for low borderline
temperature of the glass substrate. Openings are disposed on the
disconnected heating temperature equalizing plates 222 in the
second chamber 200 to function as inlets and outlets for the gas of
the gas uniform distribution module 230 and the gas recycling
module 240.
[0042] To contain the heat in the second chamber 200 and thus
maintain the temperature in the second chamber 200, a thermal
insulation pad 250 (such as a graphite blanket) is disposed on the
inner wall of the second chamber 100.
[0043] Referring to FIG. 3, there is shown a function block diagram
of a gas uniform distribution module 230 in an embodiment of the
present invention. The gas uniform distribution module 230
comprises a vapor producing unit 231, an inert gas control unit
232, a gas mixing unit 233, a mixed gas cracking heating unit 234
and a mixed gas distributing unit 235.
[0044] The vapor producing unit 231 produces selenium vapor or
sulfur vapor during the selenization or sulfurization process and
controls the output level of the selenium vapor or sulfur vapor by
pressure adjustment. The inert gas control unit 232 controls the
output level of the inert gas by pressure and flow rate adjustment.
The gas mixing unit 233 is connected to the vapor producing unit
231 and the inert gas control unit 232 to thereby mix and output
the vapor produced by the vapor producing unit 231 and the inert
gas output by the inert gas control unit 232. The mixed gas
cracking heating unit 234 is connected to the gas mixing unit 233
to thereby produce a mixed gas attributed to selenium vapor or
sulfur vapor and capable of high-temperature cracking. Unlike a
conventional selenization/sulfurization process, the
selenization/sulfurization process of the present invention not
only involves replacing selenization or sulfurization of toxic
H.sub.2Se or H.sub.2S in a vacuum environment with cracking
selenium or mixing sulfur with an inert gas in a near-atmospheric
pressure environment to render the process safe, but also has the
following technical features: the mixed gas distributing unit 235
is connected to the gas cracking heating unit 234 and the second
chamber 200; the gas output by the mixed gas cracking heating unit
234 is uniformly distributed in the second chamber 200, such that a
mixed gas attributed to selenium vapor or sulfur vapor and capable
of high-temperature cracking is distributed across the glass
substrate 1 at a uniform flow rate; the shape and size of the
orifices of the mixed gas distributing unit 235 are determined by
CFD computation and analysis, such that the gas distribution
perpendicular to the direction of the motion of the glass substrate
1 meets process requirements.
[0045] Referring to FIG. 4, there is shown a schematic view of the
mixed gas distributing unit 235 in an embodiment of the present
invention. The mixed gas distributing unit 235 is formed by
coupling together a plate 2352 and two halves of a round pipe 2351.
A main aperture 2353 is disposed on top of the pipe 2351 and
connected to the mixed gas cracking heating unit 234. The round
pipe 2351 has therein the plate 2352. A plurality of through
gas-emitting holes 2354 is disposed at the lower end of the round
pipe 2351 and the flat board 2352, such that a mixture of
selenium/sulfur vapor and an inert gas passes the through
gas-emitting holes 2354 to distribute uniformly across the glass
substrate 1.
[0046] Referring to FIG. 5, there is shown a function block diagram
of a gas recycling module 240 in an embodiment of the present
invention. The gas recycling module 240 comprises a gas drawing
unit 241, a condensation unit 242 and a collecting unit 243.
[0047] The gas drawing unit 241 connects with the second chamber
200 via a gas drawing channel (not shown) to thereby draw the
excess selenium vapor, sulfur vapor and inert gas out of the second
chamber 200 during the process. The condensation unit 242 connects
with the gas drawing unit 241 to thereby solidify, by condensation,
the selenium/sulfur vapor and inert gas drawn into the gas drawing
unit 241. The solid-state selenium/sulfur and inert gas are
recycled and reused by a mechanism for separating a gas phase and a
solid phase. The collecting unit 243 connects with the condensation
unit 242 to thereby collect solid-state selenium and inert gas thus
separated, so as to reuse the recycled solid-state selenium and
inert gas, thereby reducing material costs.
[0048] Referring to FIG. 6, there is shown a schematic view of the
rapid thermal processing device and the selenization/sulfurization
soaking device coupled together in an embodiment of the present
invention. FIG. 6 illustrates definitely the relation between the
rapid thermal processing device 10 and the
selenization/sulfurization soaking device 20, and thus FIG. 6 shows
part of the elements of the present invention. See FIG. 1 through
FIG. 5 for the other elements of the present invention.
[0049] The first chamber 100 and the second chamber 200 are
connected by an interface channel 300. The two ends of the
interface channel 300 are connected to the second gate 102 of the
first chamber 100 and the third gate 201 of the second chamber 200,
respectively, such that the interface channel 300 functions as an
interface between the first chamber 100 and the second chamber 200.
A temperature measuring device 301 is disposed between the first
chamber 100 and the second chamber 200 and positioned on the
interface channel 300. The temperature measuring device 301 is of
non-contact style. The temperature measuring device 301 measures,
in real time, the temperature of a thin-film of the glass substrate
1 while passing through the interface channel 300.
[0050] In general, the selenization/sulfurization process comprises
the following steps: introducing the glass substrate 1 into the
first chamber 100 by the first hot roller heating module 110 as
soon as the first gate 101 of the first chamber 100 opens; shutting
the first through fourth gates 101, 102, 201 and 202; starting a
vacuum ventilation system; and starting a heating system (such as
the first hot roller heating module 110 and the first heater 120
shown in FIG. 1 and the second hot roller heating module 210 and
the second heater 220 shown in FIG. 2) of the first chamber 100 and
the second chamber 200 when the first chamber 100 and the second
chamber 200 reach a low to median degree of vacuum state, say 10-2
torr, respectively. After the glass substrate 1 has been placed on
the first hot roller heating module 110 in the first chamber 100
with a low to median degree of vacuum, the first roller heating
unit 112 disposed in the first heating rollers 111 begin to heat up
the first heating rollers 111 while the first heater 120 is heating
up the glass substrate 1 quickly; meanwhile, the first heater 120
beneath the first hot roller heating module 110 heats up the first
heating rollers 111 such that the difference between the surface
temperature of the first heating rollers 111 and the temperature of
the glass substrate 1 is kept within a specific range.
[0051] At this point in time, the heating lamps 221 of the second
heater 220 of the second chamber 200 has heated up the heating
temperature equalizing plates 222, whereas the second roller
heating unit 212 disposed in the second heating rollers 211 of the
second hot roller heating module 210 is heating up the second
heating rollers 211. Also, the heating temperature equalizing
plates 222 beneath the second hot roller heating module 210 are
operating in conjunction with the second heating rollers 211, such
that the difference between the surface temperature of the second
heating rollers 211 and the temperature of the glass substrate 1 is
kept within a specific range.
[0052] By the time when the temperature in the first chamber 100
has risen to a specific temperature, both the second gate 102 of
the first chamber 100 and the third gate 201 of the second chamber
200 open; meanwhile, the temperatures of the first hot roller
heating module 110 in the first chamber 100, the second hot roller
heating module 210 in the second chamber 200, the glass substrate
1, the heating temperature equalizing plates 222 in the second
chamber 200 will be maintained within a specific temperature range.
Afterward, the first hot roller heating module 110 in the first
chamber 100 conveys the glass substrate 1 to the second chamber 200
quickly through the interface channel 300, and then the glass
substrate 1 is received by the second hot roller heating module 210
of the second chamber 200, such that the glass substrate 1
undergoes reciprocating motion in the second chamber 200. The
second gate 102 of the first chamber 100 and the third gate 201 of
the second chamber 200 shut so as to form their respective airtight
spaces as soon as the glass substrate 1 is conveyed to the second
chamber 200. In this regard, if the process is a continuous
process, the first chamber 100 can heat up the glass substrate 1
quickly in the next instance. As mentioned before, the soaking
selenization process which takes place in the second chamber 200
involves forming a CIGS thin-film by selenization/sulfurization
performed on a thin-film on the glass substrate 1 at high
temperature and in the presence of a mixture of an inert gas and
selenium/sulfur vapor produced by the gas uniform distribution
module 230 with a controllable yield.
[0053] If the process is a multi-stage soaking temperature
selenization/sulfurization process, after undergoing first-stage
soaking temperature selenization/sulfurization in the second
chamber 200, the glass substrate 1 is sent back to the first
chamber 100 in the aforesaid manner to undergo second-stage rapid
thermal processing, and then the glass substrate 1 is conveyed to
the second chamber 200 as soon as the temperature reaches the
process temperature specified for the second stage to continue with
second-stage soaking selenization/sulfurization process.
Alternatively, upon completion of the first-stage
selenization/sulfurization, the glass substrate 1 is conveyed from
the second chamber 200 to another chamber (not shown), such as
another selenization/sulfurization process apparatus, connected to
the fourth gate 202 of the second chamber 200 to continue with
rapid thermal processing and selenization/sulfurization in the
subsequent stage.
[0054] Therefore, the selenization/sulfurization process apparatus
of the present invention is characterized by two chambers for
heating up a glass substrate quickly and performing
selenization/sulfurization on the glass substrate to not only
prevent the glass substrate from staying at a soaking temperature
of a softening point for a long period of time but also increase
the thin-film selenization/sulfurization temperature according to
the needs of the process to thereby reduce the duration of soaking
selenization/sulfurization, save energy, and save time. The glass
substrate undergoes reciprocating motion in the chambers to not
only attain uniform temperature throughout the glass substrate but
also distribute a selenization/sulfurization gas across the glass
substrate uniformly during the selenization/sulfurization
operation. Furthermore, recycled liquid selenium/sulfur and inert
gas can be reused to thereby reduce material costs.
[0055] The present invention is disclosed above by preferred
embodiments. However, persons skilled in the art should understand
that the preferred embodiments are illustrative of the present
invention only, but should not be interpreted as restrictive of the
scope of the present invention. Hence, all equivalent modifications
and replacements made to the aforesaid embodiments should fall
within the scope of the present invention. Accordingly, the legal
protection for the present invention should be defined by the
appended claims.
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